1. Field of the Invention
The present invention relates to an image creating apparatus for creating a variety of images for expressing a variety of objects on a two-dimensional plane.
2. Description of the Prior Art
In recent years, there has arisen a requirement for a method of interaction between a human being and a computer, such as a man-machine interface or human interface. Thus, an intuitive interactive method using the five senses of a human being on the basis of techniques, such as artificial reality (AR) and virtual reality (VR), has been realized. Also, in the field of personal computers, there have been realized structures typified by computer games having high speed image creation and animation functions and enabling images to be changed in accordance with the operation performed by a human being. Also, information processing apparatuses, such as personal computers for home use, have been enabled to create and display a high-quality dynamic image by using computer graphics, thanks to improvement in performance. A further improvement in the quality of an image which is displayed has been required.
Since the performance of the computer system has been improved, an artificial creature composed of independent object groups has been considered feasible to be created. Moreover, an attempt has also been made to realize a world in a computer in which the artificial creature lives. An image creating apparatus for displaying an image of the motion of an artificial creature of the foregoing type has been disclosed by the inventors of the present invention (refer to U.S. Ser. No. 08/369,110). The foregoing image creating apparatus inputs a motion pattern which is considered and required by the artificial creature as a command. In accordance with the command, required images are selected from a multiplicity of image patterns to create and display a continuous image. Thus, the motion of the artificial creature can be visualized and a virtual experience can be realized. The foregoing image creating apparatus converts image data expressed with three-dimensional coordinates into two-dimensional coordinates in accordance with three-dimensional image data obtained from a variety of photographed objects including an artificial creature thereby to create an image which is displayed on a two-dimensional screen.
To enable the image creating apparatus of the foregoing type to move the artificial creature in various environments to display the motion of the artificial creature like an actual creature to provide further improved reality to a viewer, an image must be created which is capable of expressing a variety of factors including other artificial creatures, natural objects and background as well as the subject artificial creature as if they were seen by the eyes.
For example, a soft wind, rain, an action of a bird or fish, and the like, causes ripples, sway, wave or spray to be generated on the water surface of an actual lake, pond, or the like. Moreover, the water surface reflects plants and buildings existing on the shore. In addition, an image of a bird flying in the sky is sometimes reflected on the water surface. If the computer graphics is able to display a created image of the water surface having the above-mentioned movements, reality can be given to the whole image.
However, it is difficult for the improved performance of the present personal computer to create a dynamic image in real time while simulating the foregoing movements. In particular, when a dynamic image of a type expressing an object, such as an artificial creature or a character of a computer game, moving on a background image including the water surface is displayed, the dynamic image must be created in real time to follow an indefinite movement of the object.